https://discourse.pi-hole.net/t/commonly-whitelisted-domains/212

host-whitelist-common.txt

# Apple
appleid.apple.com
itunes.apple.com
captive.apple.com
gsp1.apple.com
www.apple.com
www.appleiphonecell.com

# Google
clients4.google.com 
clients2.google.com
s.youtube.com
video-stats.l.google.com
android.clients.google.com
reminders-pa.googleapis.com
firestore.googleapis.com
googleapis.l.google.com

# Microsoft
www.msftncsi.com
outlook.office365.com
products.office.com
c.s-microsoft.com
i.s-microsoft.com
login.live.com
login.microsoftonline.com
g.live.com
dl.delivery.mp.microsoft.com
geo-prod.do.dsp.mp.microsoft.com
displaycatalog.mp.microsoft.com
officeclient.microsoft.com

# Xbox Live

clientconfig.passport.net 
events.data.microsoft.com
v20.events.data.microsoft.com
client-s.gateway.messenger.live.com
xbox.ipv6.microsoft.com
device.auth.xboxlive.com
www.msftncsi.com
title.mgt.xboxlive.com
xsts.auth.xboxlive.com
title.auth.xboxlive.com
ctldl.windowsupdate.com
attestation.xboxlive.com
xboxexperiencesprod.experimentation.xboxlive.com
xflight.xboxlive.com
cert.mgt.xboxlive.com
xkms.xboxlive.com
def-vef.xboxlive.com
notify.xboxlive.com
help.ui.xboxlive.com
licensing.xboxlive.com
eds.xboxlive.com
www.xboxlive.com
v10.vortex-win.data.microsoft.com
settings-win.data.microsoft.com

# Skype
s.gateway.messenger.live.com
client-s.gateway.messenger.live.com
ui.skype.com
pricelist.skype.com
apps.skype.com
m.hotmail.com
sa.symcb.com
s{1..5}.symcb.com 

# Spotify
spclient.wg.spotify.com
apresolve.spotify.com

# Plex
plex.tv
tvdb2.plex.tv
pubsub.plex.bz
proxy.plex.bz
proxy02.pop.ord.plex.bz
cpms.spop10.ams.plex.bz
meta-db-worker02.pop.ric.plex.bz
meta.plex.bz
tvthemes.plexapp.com.cdn.cloudflare.net
tvthemes.plexapp.com
106c06cd218b007d-b1e8a1331f68446599e96a4b46a050f5.ams.plex.services
meta.plex.tv
cpms35.spop10.ams.plex.bz
proxy.plex.tv
metrics.plex.tv
pubsub.plex.tv
status.plex.tv
www.plex.tv
node.plexapp.com
nine.plugins.plexapp.com
staging.plex.tv
app.plex.tv
o1.email.plex.tv
o2.sg0.plex.tv
dashboard.plex.tv